The DoH has advised that GPs should avoid giving the Enzira jab to children aged under five years (Photograph: SPL)

Data from Australia suggest there has been a higher than expected level of febrile convulsions in children given the Fluvax vaccine.

Fluvax will be marketed in the UK for the 2010/11 influenza vaccination season by Pfizer as Enzira. CSL Biotherapies will offer it as a generic influenza vaccine.

There appears to be a rate of febrile convulsions of about one per 100 for children vaccinated with Fluvax. This increased risk is understood to be a product-specific reaction.

In a letter to GPs, the DoH director of immunisation for England Professor David Salisbury said that since other influenza vaccines were available, GPs should avoid giving Enzira or CSL Biotherapies' generic jab to children aged under five.

Professor Salisbury said GPs should check which products they have ordered and ensure that they have stocks of other influenza vaccines.

He stressed the importance of ensuring children in clinical risk groups are vaccinated.

A Pfizer spokesman said that the cause of the increased frequency of febrile convulsions was unknown and that investigations were ongoing.

He said the company supported the UK's precautionary approach, but that there was no evidence that the vaccine poses any increased risks to other groups, including pregnant women and those aged over 65.

Professor Salisbury said that the MHRA would continue to closely monitor reactions to the vaccine and would issue further advice in advance of the 2010 influenza immunisation programme.